High sensitivity electrical relay



Sept. 2,, 1958 F. A. HOOVER EIAL HIGH SENSITIVITY ELECTRICAL RELAY Filed Aug. 25, 1955 u ET OVN. v TOG NOR M WHO 2 ma m K T N 0 0 Y 4 B Patented Sept. .2, 1958 ice j HIGH SENSITIVITY ELECTRICAL RELAY Frank A. Hoover, Albuquerque, N. Mex., and Abraham I. Dranetz, Metucheu, N. J., assignors to Gulton Industries, Inc., Metuchen, N. 1., a corporation of New Jersey Application August 25, 1955, Serial No. 530,580

8 Claims. (Cl. 200-87) Our invention relates to high sensitivity relays and in particular to those types of relays which utilize torsion mounted arms.

An important object of our invention is to provide a sensitive electrical relay which is not affected by external shock and vibration.

A further object of our invention is to provide an electrical relay whose sensitivity may be adjusted.

Other objects and advantages of our invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same.

Figure l is a horizontal plan View, partly in section, of an embodiment of our invention,

Figure 2 is a side, elevation, partly in section, of the embodiment of Figure 1,

Figure 3 is an end elevation, partly in section, of the embodiment of Figure 1, and

Figure 4 is a section along the line 4-4 of Figure 1.

In the drawings, wherein for the purpose of illustration, is shown a preferred embodiment of our invention, the numeral designates the relay case, the numeral 11 designates the relay arm, the numeral 12 designates the relay contacts, and the numeral 13 designates the relay base. The numeral 14 designates the solenoid armature, the numeral 15 designates the solenoid coil, the numeral 16 designates the mounting screws, and the numeral 17 designates the upper fixed contact.

The numeral 18 designates the lower fixed contact, the numeral 19 designates the relay frame, the numeral 20 designates the relay arm suspension, and the numeral 21 designates the tension adjustment screws. The numeral 22 designates the relay arm suspension anchor, the numeral 23 designates the double spiral cantilever springs, the numeral 24 designates the retaining springs, the numeral 25 designates the degassed liquid, and the numeral 26 designates the pressure relief valve. The numeral 27 designates the relay arm lead wire, the numeral 28 designates the lower fixed contact lead wire, the numeral 29 designates the upper fixed contact lead wire, the numeral 30 designates the solenoid lead wires, and the numeral 31 designates the sealing strips. numeral 32 designates the mounting key, the numeral 34 designates the mounting block, the numeral 35 designates the retaining rings, and the numeral 36 designates the mounting shell. The numeral 37 designates the slot in which mounting key 32 is seated. Holes 38 are provided so as to permit armature 14 to be properly centered and lock ring 39 holds mounting shell 36 in position.

In the preferred embodiment of our invention, shown in the figures, the relay base 13 is mounted to the outer case 10 by means of mounting screws 16 and rigidly alfixed thereto. liquid 25 such as carbon tetrachloride or the like, under pressure, and is hermetically sealed. Pressure relief valve 26 is provided to act as a pressure release in the event Outer case 10 is filled with a degassed The 1 that the pressure within the case 10 becomes excessive. Relay arm 11 is constructed so that its average density is substantially equal to the density of liquid 25. For example, this may be accomplished by constructing relay arm 11 of light weight plastic with a sealed hollow interior chamber containing air. A thin light weight metallic conductor may then be bonded along the length of arm 11 to electrically connect arm lead 27 to arm contacts 12. Arm lead 27 is brought out through a seal in case 10. This additional metallic conductor is not required if arm 11 is constructed of conductive material.

Lower fixed contact 18 is afiixed to base 13 and may be.

insulated therefrom or electrically connected thereto depending upon the application in which the relay is to be used. Lower fixed contact lead 28 is electrically connected to lower fixed contact 18 and brought out through a seal in outer case 10.

Upper fixed contact 17 is insulated from frame 10 and electrically connected to upper fixed contact lead 29 which is brought out through a seal in outer case 10. Solenoid armature 14 is fixedly attached to relay arm 11 and is acted upon by solenoid coil 15 whose electrical leads 30 are brought out through seals in outer case 10.

When current flows in the external electrical circuit associated with leads 30, solenoid armature 14 is pulled down and contact is made between 12 and 17 and the associated external electrical circuit is closed. At the same time contact is broken between 12 and 18 and the associated external electrical circuit is opened. When no current flows in solenoid coil 15, solenoid armature 14 is moved upwards by the action of the relay arm suspension 20 and the contact between 12 and 18 is closed and that between 12 and 17 is, opened.

Relay arm 11 is center supported by relay arm suspension 20. This suspension is of the torsion type and may be constructed of the bifilar wires illustrated in the figures or a fiat strip or a single torsion wire on each side of armature 11. The sensitivity of the relay is adjusted by adjusting the tension of the relay arm suspension 20. This is accomplished by adjusting tension adjustment screws 21 which are threaded differentially where they enter the rotatable housings 36 and at their ends where they enter the suspension anchor mounts 34. Tension adjustment screws 21 are made so that they cannot fall inside housings 36 in their most extreme clockwise positions. The embodiment of our invention illustrates two tension adjustment screws 21 used in conjunction with the associated units described but relays embodying our invention may be constructed utilizing only a single such adjustment. Relay arm suspension anchor 22 is held in position by a pair of double spiral cantilever springs 23 which are suitably held by mounting keys 32 and retaining rings 35. Retaining spring 24 serves to eliminate any play due to looseness of fit in the assembly. Pin 32 fits into a keyway or slot 37 to prevent rotation of mount 34 with respect to housing 36 so rotation of 21 moves the associated relay suspension anchor mount 34 toward or away from case 10 and thus increases or decreases the tension on assocaited relay arm suspension 20 through springs 23. Housing 36 may be rotated within case 10 by means of a spanner wrench or similar tool inserted arm 11 enabling it to resist rotational motion caused by linear acceleration in any of the three coordinate axes.

rents in the solenoid coil 15. 25 also providesbetter electrical 'resistancebetween the contacts and improves the arc suppression when the contacts are opened Liquid 25 impregnates solenoid coil and by conducting heat away from 15, lessens the chance of the coils burning 'out'due to current overloads.

The pressure relief plug 26 serves as a pressure relief mechanism to prevent blowout at elevated temperatures.

The average density of relay arm ll is made equal to the density of liquid 25 so that there is no effect on the relay assembly due to external shock or vibration.

Because of the increase in resistance between the contacts, the employment of the torsion suspension, and the utilization of the degassed fluid within a hermetically sealed case, it is feasible and practical tornanufacture electrical relays, in accordance with our invention, which are smaller in sizefcapable of higher current carrying capacity, and less affected by external shock and vibration than relays which are now being manufactured and used. While we have shown only one embodiment of our invention, it will be recognized that this is only by way of illustration of general principles and that our inven-' tion is not limited to the particular means illustrated, but various changes, modifications and alterations may be made without departing from the spirit of the invention or the scope of the subjoined claims. 7

Having thus described our invention, we claim 1. An electrical relay comprising an arm mounted on a pair of bifilar torsion suspensions; each said suspension being formed of thin resilient material; each said suspension being fixedly attached to one side of said arm and substantially at right angles thereto; said arm having at least one electrical contact affixed thereto; enclosing means isolating said relay from the surrounding medium; the end of one of said bifilar torsion suspensions opposite said armbeing aflixed to tension adjusting means; the end of the other of said bifilar suspensions being aflixed to said enclosing means; fluid means containedwithin said enclosing means; the average density of'said arm being substantially equal to the density of said fluid means; said tension adjusting means comprising a first cup-shaped housing within said enclosing means, a second cupshaped housing mounted within said first housing and movable with respect thereto, said first housing being keyed whereby the relative movement of said second housing with respect to said first housing is limited, a retaining ring aflixed to the inner surface of said second '7 housing, said retaining ring supporting a pair of cantilever springs to which is attached an anchor, said bifilar torsion being affixed to said anchor, and means-for adjusting the position of said second housing with respect to said first housing.

' 2. An electrical relay as described in claim 1 wherein said means for adjusting the position of said second housing with respect to said first housing is a diflerentially threaded screw.

3. An electrical relay as described in claim 1 wherein said first housing is movable with respect to said enclosing means.

4 An electrical relay comprising an arm mounted on a pair of bifilar torsion suspensions; each of said bifilar suspensions being formed of thin resilient material; each said bifilar suspension being afiixed to one side of said arm and substantially at right angles thereto; said arm having at least one electrical contact aflixed thereto; enclosing means isolating said relay from the surrounding medium, the ends of both of said bifilar suspensions opposite said arm being affixed 'to tension adjusting means; fluid means contained within said enclosing means; the average density of said arm being substantially equal to the density of said fluid means.

5. An electrical relay comprising in combination an elongated arm having at least one contact fixed near one end thereof, a thin reslient torsion suspension element fixedly attached substantially at right angles to said arm at a position spaced from said contact to provide a pivot point about which said arm is disposed to move, magnetic actuating means to cause said arm to move disposed on the other side of said pivot point from said contact, an envelope for isolating said arm and said actuating means from the surroundingmedium, one end of said torsion suspension element being fixed with respect to said envelope, and tension and torsion adjusting means connected to the other end of said torsion suspension element constructed for manipulation externally of said envelope thereby to obtain a fine degree of control over the operation of said relay.

6. An electrical relay as described in claim 5 wherein a fluid is contained within said envelope, said fluid having a density substantially equal to the density of said arm.

7. An electrical relay as described in claim 5 wherein a fluid is contained within said envelope, said fluid having a density substantially equal to the density of said arm.

8. An electrical relay comprising in combinationan elongated arm having at least one contact connected thereto, a pair of bifilar torsion suspension elements each formed of a thin resilient material, fixedly attached substantially at right angles to said arm to serve as a pivot for the motion of said arm, means for magnetically actuating said arm, said actuating means and said contact being disposed on opposite sides of said pivot, enclosing means for isolating said relay from the surrounding medium, wherein the end of at least one of the bifilar suspension elements of said pair is fixed to tension and torsion adjusting means, and the end of the other ele ment of said pair is fixed with respect to said enclosing means, and a fluid contained within said enclosing means, the average density of said arm and of said fluid being substantially equal.

References Cited in the file of this patent UNITED STATES PATENTS 405,989 Burke June 25,

496,500 Weston May 2, 1893 2,339,676 Bucklen Ian. 18, 1944 2,635,155 Barr Apr. 14, 1953 2,706,756 Brewer Apr. 19, 1955 FOREIGN PATENTS 170,117 Great Britain Oct. 17, 1921 mums) 2511mm? r'alhii'i UFFIQE CETIFICATE Q? Q EQTCEQN Patent No. 2,850,593 September 2, 1958 Frank A Hoover et al0 It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below" Column 3, line 19, for fiuid" read me fluid column 4, lines 32 to 35, strike out "a fluid is contained Within said envolope, said fluid having a density substantially equal to the density of said arm," and insert instead said resilient torsion rsuspension element is of a bifilar type. a

Signed and sealed this 18th day of November 1958.

(SEAL) Attest:

KARL H, AXLINE ROBERT E. ATSON Attesting Officer Commissioner of Patents cuttin on [E3 Tfliihll'l UFFKQE CETIFIQATE @F REC Patent No, 2,850,593 September 2, 1958 Frank A, Hoover et al0 It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,

Column 3, line 19, for "ffuid' read we fluid column 4, lines 32 to 35, strike out "a fluid is contained Within said envelope, said fluid having a density substantially equal to the density of said arnn and insert instead said resilient torsion :xsuspension element is of a bifilar type a Signed and sealed this 18th day of November 1958.

(SEAL) Attest:

KARL H,a AXLINE RQBERT C. WATSON Attesting Officer Commissioner of Patents 

